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arXiv 2301.04495cond-mat.str-el
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自旋玻璃Fe $_{x}$ Cr $_{1-x}$中自旋动力学在冻结过程中的演化

Evolution of the spin dynamics during freezing in the spin-glass Fe$_{x}$Cr$_{1-x}$

Steffen Säubert, Christian Franz, Johanna K. Jochum, Georg Benka, Andreas Bauer, Stephen M. Shapiro, Peter Böni, Christian Pfleiderer

摘要:

在铁-铬系统中,Fe $_{x}$ Cr $_{1-x}$,当铁的铁磁性被抑制时,出现宽的自旋玻璃行为圆顶,铬的反铁磁性作为铁含量$x$增加的函数出现。由于高温状态和特征团簇尺寸都作为$x$的函数而变化,因此可以在单个同构材料系统中比较自旋玻璃行为的不同状态。在这里,我们报告的自旋动力学的冻结过程中的自旋玻璃状态不同的铁浓度($x = 0.145$,$0.175$,$0.21$)使用零强度调制(MIEZE)光谱的研究。在研究的参数范围内,实验观察到的弛豫过程可以很好地描述在拉伸指数。在重入团簇玻璃区,$x = 0.145$,这种行为持续到高温。相比之下,在超顺磁制度,$x = 0.175$和$x = 0.21$,一个单一的弛豫时间在高温下观察。对于所有研究的样品,自旋弛豫表现出与幂律一致的动量依赖性,提供证据的自旋弛豫的色散特性。

英文摘要:

In the iron--chromium system, Fe$_{x}$Cr$_{1-x}$, a wide dome of spin-glass behavior emerges when the ferromagnetism of iron is suppressed and the antiferromagnetism of chromium emerges as a function of increasing iron content $x$. As both, the high-temperature state and the characteristic cluster size vary as a function of $x$, different regimes of spin-glass behavior may be compared in a single, isostructural material system. Here, we report a study of the spin dynamics across the freezing process into the spin-glass state for different iron concentrations ($x = 0.145$, $0.175$, $0.21$) using Modulation of IntEnsity with Zero Effort (MIEZE) spectroscopy. In the parameter range studied, the relaxation process observed experimentally may be described well in terms of a stretched exponential. In the reentrant cluster-glass regime, $x = 0.145$, this behavior persists up to high temperatures. In comparison, in the superparamagnetic regime, $x = 0.175$ and $x = 0.21$, a single relaxation time at elevated temperatures is observed. For all samples studied, the spin relaxation exhibits a momentum dependence consistent with a power law, providing evidence of a dispersive character of the spin relaxation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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